Spill metric
Encyclopedia
A spill metric is a heuristic metric used by register allocators
to decide with registers to spill. Popular spill metrics are:
Where cost is the estimated cost of spilling a value from registers into memory.
Register allocation
In compiler optimization, register allocation is the process of assigning a large number of target program variables onto a small number of CPU registers...
to decide with registers to spill. Popular spill metrics are:
- cost / degree - introduced in Chaitin's algorithmChaitin's algorithmChaitin's algorithm is a bottom-up, graph coloring register allocation algorithm that uses cost/degree as its spill metric. It is named after its designer, Gregory Chaitin...
- cost / degree2 - emphasizes the spill's effect on neighbours
- cost - emphasizes run time
- minimising number of spill operations
Where cost is the estimated cost of spilling a value from registers into memory.